WHAT CAUSES SINKHOLES

KING JESUS IS COMING FOR US ANY TIME NOW. THE RAPTURE. BE PREPARED TO GO.

SINK HOLES

NUMBERS 16:30-32
30  But if the LORD make a new thing, and the earth open her mouth, and swallow them up, with all that appertain unto them, and they go down quick into the pit; then ye shall understand that these men have provoked the LORD.
31  And it came to pass, as he had made an end of speaking all these words, that the ground clave asunder that was under them:
32  And the earth opened her mouth, and swallowed them up, and their houses, and all the men that appertained unto Korah, and all their goods.

NUMBERS 26:10
10  And the earth opened her mouth, and swallowed them up together with Korah, when that company died, what time the fire devoured two hundred and fifty men: and they became a sign.

ISAIAH 28:18-19
18  And it shall come to pass, that he who fleeth from the noise of the fear shall fall into the pit; and he that cometh up out of the midst of the pit shall be taken in the snare: for the windows from on high are open, and the foundations of the earth do shake.
19  The earth is utterly broken down, the earth is clean dissolved, the earth is moved exceedingly.

LUKE 21:11
11  And great earthquakes shall be in divers places, and famines, and pestilences; and fearful sights and great signs shall there be from heaven.

Why Sinkholes Open Up

Get the science behind sinkholes and which areas are more prone to them.

People stop to look at a 40- to 60-foot sinkhole that partially collapsed a building in Clermont, Florida.

Photograph by Gerardo Mora, Getty Images

Jeremy Berlin - National Geographic -Published August 12, 2013

Last night a sinkhole opened beneath a central Florida resort, collapsing one three-story building and pulling another slowly into the ground.

An estimated 35 guests escaped unharmed as the 50-foot (15-meter) wide, 15-foot (4.5-meter) deep crater broke glass, snuffed lights, and shook the ground at the Summer Bay Resort in Clermont, about ten miles west of Walt Disney World.It's the second time this year a major sinkhole has roiled the region. In late February a mouth 20 feet (6 meters) wide swallowed 37-year-old Jeff Bush as he slept in Seffner, Florida, inhaling his entire bedroom. Five others in the house escaped without injury, including Jeremy Bush, who tried in vain to save his brother.That tragedy left the community shaken and full of questions. To find out more about how and why sinkholes happen, National Geographic sat down earlier this year with Randall Orndorff of the U.S. Geological Survey.

What is a sinkhole?

A sinkhole is basically any collapsed or bowl-shaped feature that's formed when a void under the ground creates a depression into which everything around it drains. (Gallery: Sinkholes from around the world.)

How many types of sinkholes are there?

There are two basic kinds. One is called a cover-subsidence sinkhole. You find these in places like the Shenandoah Valley, or in sandier soils where you've got a void underground. As the soil above transports itself into that cave in the rock, the ground slowly subsides. So it's not catastrophic. It subsides over time. It could be over years; it could be over hundreds of thousands of years.The other kind is what we call a cover-collapse sinkhole. This is the one that makes the news. It tends to occur in clay, because clay holds soil together like glue. As with cover subsidence, soil is leaching into a cave below, but it creates a void in the soil that moves upward. You can't see it on the surface. Then, all of a sudden, the bridge over top of that void can't hold anymore and it collapses—just like we saw in Florida last week.

Do any human activities induce sinkholes?

Sure. Sometimes in karst areas [irregular landscapes formed when soluble rocks like limestone dissolve], when you drill a well—looking for water or for mining purposes—as you're pulling water out of the ground, you're lowering the groundwater table. That creates almost a toilet-flushing effect. You're lowering that groundwater level, and the soil that was sitting above just falls out. That's one way.We also induce sinkholes when we start putting up parking lots and buildings and changing what we call the hydrologic regime. Instead of the water naturally soaking into the ground, it's now running off and being concentrated—being put into the ground at one point. (See "Guatemala Sinkholes Created by Humans, Not Nature.")

Which states, areas, or regions are most vulnerable?

Well, if you're talking about limestone, you're talking about the eastern U.S. Obviously we start out with Florida; almost the entire state can be classified as karst, which means it has the potential for sinkholes.

But then you look at other limestone terrain. So the Great Valley, from Pennsylvania—even eastern New York—all the way down through Tennessee to Alabama is an area that's quite prone. So are the Ozarks of Missouri. And Indiana, and the southeastern corner of Minnesota.Basically from Oklahoma east is where the rainfall averages about 30 inches per year. And that tends to be a dividing line for limestone. But in the arid environments to the West—like the Black Hills of South Dakota and Wyoming, areas in New Mexico, parts of Oklahoma—you have gypsum, which is another soluble rock. It's a tough rock and fine when it's dry, but it tends to dissolve quite rapidly if a lot of rain runs through it real fast.And then there's salt, which we've dealt with in Daisetta [a town in east Texas that sits on a salt dome and was the site of a 600-foot-wide, 150-foot-deep sinkhole in 2008]. There was a similar situation last summer in Bayou Corne, in Louisiana—a salt dome that collapsed. And we all know that when you put salt in a glass and you put water in it, the salt disappears because it's soluble.

What about other countries?

Mexico and Belize is a karst area. So are parts of Italy. The term "karst" actually comes from a Slovenian [word and region] called Kras, and that whole area of old Yugoslavia—Slovenia, Croatia—is a major sinkhole zone. Huge areas of China are too. And also Russia. Basically it's all over the world. I'm part of a group that's thinking about putting together a karst map of the world. (Pictures: Sinkhole swallows truck in Beijing.)

What are the warning signs of a sinkhole? Is there any way to prevent one from occurring?

Sometimes there may not be any warning signs. But sometimes there are. Keep your eyes open for fresh cracks in the foundations of houses and buildings. Or if suddenly a door frame is skewed and your door doesn't shut the way it used to. Anytime you see something like that inside the building itself, that can be a warning sign.Outside around the house or building, on the ground surface, you might start seeing cracks in the ground or little depressions. The soil basically pipes down into that cave. And if there's a small area that starts that way, that may be the beginning of a collapse. Or a tree will all of a sudden start leaning. Don't go right up to it, but see if the tree is leaning because the root system is gone or because the ground around it is subsiding.As far as prevention, if you're lucky enough to see that there's a void beneath a structure, there has been limited success digging out all the soil and getting down to the bedrock, then grouting it with concrete and putting in a lot of bric-a-brac—large pieces of rock, then smaller pieces on that—to try to mitigate it. But if it's under a building [as was the case in Florida last week), then I don't think you'll have much luck.

What is the biggest sinkhole on record? The deadliest? The costliest in terms of property or infrastructure damage?

As far as collapses, loss of life has tended to be minimal, thank goodness. That's because sinkholes are localized. A lot of the fatal ones I've seen have happened on highways, where people were driving down the road and drove right into them. A lot of people who have died in sinkholes were just standing right there when [the collapse occurred].The one in Guatemala in 2010—that was just an incredible, incredible hole that looked like it was bottomless. To [geologists], that one is probably one of the more spectacular. Of course, that wasn't in a karst area. That was because a big sewage line, or a big storm drain, was buried quite deeply.Probably the most spectacular one in the U.S. was the one in Winter Park, Florida, in 1981, where the Porsches [at a local dealership] fell into it and it took up a whole city block. When we scientists talk about spectacular sinkholes, that one usually tops the list. And the Daisetta one in Texas, because that was one of the first ones caught on video—you could watch it happen.

What happens after a sinkhole is done collapsing?

Generally, if you don't do anything with it, the hole will plug itself with soil. But then it's a natural drain, so as it rains water flows into it, and it becomes a natural inlet into the groundwater. Sometimes it'll become what we call an "open throat," where you can see the rock at the bottom, which can be an entrance into the cave system. Depending on the depth of the water table, it can also fill up with water. And then you have yourself a pond.

Is the frequency of sinkholes increasing these days?

The answer is we don't know, because we just don't have enough data. Sinkholes aren't widespread events like hurricanes or earthquakes. They're very localized. A lot of karst areas are agricultural, because they tend to have very good farming soil. And sinkholes happen all the time in farmers' fields.But there's no national or international sinkhole database. Still, as our population grows and we develop more areas that are susceptible, we seem to be seeing more sinkholes—and more stories about humans being impacted by them.

Plateau sinkhole deepens as motorists watch and wait

City of Montreal says repairs are planned for some future date

CBC News-Posted: Aug 16, 2013 8:24 PM ET-Last Updated: Aug 16, 2013 8:23 PM ET

Several concerned motorists have called the City of Montreal's 311 hotline, worried about a sinkhole at the corner of St. Denis and Roy Streets that appears to be getting deeper daily.

• Sinkhole swallows backhoe in downtown Montreal
• Huge sinkhole opens in Montreal after student protest

The sinkhole is at the southeast corner of Roy and St. Denis streets. (Google Map)A spokesman for Montreal's Plateau borough said the borough is aware of the problem. However, it's confident the road will not cave in, as the ground underneath the asphalt is shifting but is not hollow.
A Concordia University civil engineering professor is less certain."With continued heavy traffic everyday, I expect this could really sink more," said Adel Hanna, calling the two-foot deep depression a "potential sinkhole."

SINKHOLES SWALLOW PORTION OF FLORIDA RESORT
http://www.cnbc.com/id/100956354

Overdevelopment widens Florida sinkhole problem

Published: Thursday, 15 Aug 2013 | 12:56 PM ET

By: Diana Olick | CNBC Real Estate Reporter

A portion of a building swallowed by a sinkhole Monday in Clermont, Fla.

Sinkholes may be as old as the earth itself, but the increase in sinkhole activity is new. The rush to reason why has put scientists, engineers and real estate developers at odds.Some geological experts believe the sinkhole activity is increasing because developers are pumping more water out of the ground for new projects or for agricultural use. While acid in the water itself is what causes the limestone under much of Florida to dissipate and create the holes, the water also acts as a support. Add water from heavy rains on the top soil, and you've got a bigger problem.It is even beginning to weigh on the recovering real estate market in Florida.

Play Video

Florida sinkhole just outside of Disney World

CNBC's Diana Olick has the latest on the 100 foot sinkhole in Florida swallowing up a building at a resort just outside of Disney World."As builders are forced to go farther and farther out of cities in search of developable land, compromises such as building on less than ideal sites have to be made to deliver competitively priced properties," said Peter Zalewski, an expert in Florida real estate development. "We think this factor is only going to contribute to the sinkhole problem in the future on the Florida peninsula. At the end of the day, technology can only serve as a stopgap against Mother Nature."Unlike hurricanes, noted Zalewski, one can neither predict a sinkhole disaster nor really prepare for it. While developers do have to do some drilling in order to comply with building codes, it is impossible to know if a sinkhole will develop even a year or two after the structure is completed.At least with rising tides, property owners can opt to buy on higher ground some distance from the coast," said Zalewski. "As Florida's population grows and development continues, we expect sinkholes to become a bigger and bigger issue for homeowners with no clear solution in place."

Scott Iskowitz | AP

An excavator checks the sinkhole in the bedroom of the home of Jeff Bush during demolition March 4, 2013, in Seffner, Fla.The insurance industry in Florida has taken note. Florida law requires insurers to cover "catastrophic ground collapse," and many homeowners buy additional riders to cover more minor damage.

"The number of insurance claims for sinkhole damage has increased significantly over the last several years. According to Office of Insurance Regulation, total reported claims in Florida increased from 2,360 in 2006 to 3,135 in 2010, according to information from the website of Citizens Property Insurance Corp. "The Florida Insurance Commissioner has identified sinkhole claims as a major cost-driver and expressed concern that these claims could threaten the solvency of Florida's property insurance market."Sinkhole insurance can run anywhere from around $200 to $2,000 depending on where a home is located. The Tampa Bay area is considered "Sinkhole Alley," but some have referred to Florida as the "Swiss Cheese State."In 2012, Citizens collected $56.7 million in sinkhole premiums, but estimates sinkhole losses for 2012 totaling $18.7 million, according to its website."Mother Earth controls this," said Paul Caldwell, president and general manager of the Summer Bay resort where Sunday's collapse occurred. He said its developer does not build in "dense" areas. "We test as we develop."

Jim Damaske | St. Petersburg Times | AP

Two sinkholes in the backyard of a house in Tarpon Springs, Fla., on June 16, 2011.

Still, one third of the sinkhole activity recorded since 1960 occurred in the last 13 years; half of that happened in the last three years."In the last probably five or six years, yeah, there's been a boom in more sinkholes being tested, confirmed," said Frank Vitale of L.R.E. Ground Services, a sinkhole remediation company in business for the past 25 years. He said his company has done over 4,500 jobs, large and small.
(Read more: Home builders buoyed by buyers)

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"There's definitely more work in the last five years," he said. "It could be a lot of different things. It could be the aquifer. It could be settlement issues, clay issues, buried debris. There's a million factors that can play into it, and that's why it's really important for an engineer to come in and assess the problem."
—By CNBC's Diana Olick. Follow her on Twitter @Diana_Olick.